I posted about the underside of a cabinet: Update

I have an update, but scared to try to take a picture. The mold affects me horribly, but not him. My fiancé noticed that there was also mold growing around the rim of the toilet, so he took the top of the tank lid off. He found the source of that mold. The mold started in the toilet and every flush is possibly just spreading around spores. The mold then grew on the underside of the cabinet. The water supply was shut off and he sprayed odo-ban in there. We're just baffled how this was allowed to exist for so long.

No, we will not be cleaning the toilet properly, it will be thrown out and replaced. No one can use the downstairs bathroom now.